KPNQwest NV's fiber-optic network, Europe's largest, could be shut down if the trustees of the bankrupt Internet services company find that not enough customers have paid their dues and an advance on June fees in the past days.

Late last week, the trustees asked KPNQwest customers to pay outstanding bills and an advance for June, so the company would have enough funds to keep its network online. Originally, customers had until close of business on Monday to pay, but the deadline was extended until Tuesday, a source close to the trustees said.

Keeping the network running would give customers more time to look for an alternate carrier, while the trustees have more time to find a buyer and maximize proceeds for the creditors because an operating business is worth more than a defunct business. IT services company TietoEnator Corp. uses KPNQwest's backbone to connect its offices in 10 countries and is one of the KPNQwest customers that was asked to pay. The company had not done that by late Monday afternoon, said J